The response of Phaeodactylum tricornutum to quantum dot exposure: Acclimation and changes in protein expression

• The effect of CdSe/ZnS quantum dots (QDs) on a marine diatom was investigated.
• Acclimation to QDs reduced the growth inhibition induced by nanoparticles.
• Glutathione increase at the end of the lag phase was a response to cellular stress.
• Expression of selected defence genes was up-regulated in acclimated algae.
• Acclimated cells exhibited extensive changes in proteome with respect to the control.

Nanotechnology has a great potential to improve life and environmental quality, however the fate of nanomaterials in the ecosystems, their bioavailability and potential toxicity on living organisms are still largely unknown, mainly in the marine environment. Genomics and proteomics are powerful tools for understanding molecular mechanisms triggered by nanoparticle exposure. In this work we investigated the effect of exposure to CdSe/ZnS quantum dots (QDs) in the marine diatom Phaeodactylum tricornutum, using different physiological, biochemical and molecular approaches. The results show that acclimation to QDs reduced the growth inhibition induced by nanoparticles in P. tricornutum cultures. The increase of glutathione observed at the end of the lag phase pointed to cellular stress. Transcriptional expression of selected stress responsive genes showed up-regulation in the QD-exposed algae. A comparison of the proteomes of exposed and unexposed cells highlighted a large number of differentially expressed proteins. To our knowledge, this is the first report on proteome analysis of a marine microalga exposed to nanoparticles.